FIG 1.
Responses of ceftazidime-resistant E. cloacae to continuous infusion of ceftazidime combined with two different concentration-time profiles of avibactam in the hollow-fiber model. Results are shown for isolate E. cloacae 293HT96 (stably derepressed AmpC; MIC ceftazidime, >128 mg/liter; MIC ceftazidime-avibactam, 4 mg/liter [with avibactam fixed at 4 mg/liter {59}]). ◇, untreated growth control; ◽, continuous infusion of ceftazidime (8.2 mg/liter) and avibactam (1.6 mg/liter); ○, continuous infusion of ceftazidime (8.2 mg/liter) with a single-dose profile of avibactam (Cmax, 31 mg/liter at 0.5 h). The dotted line represents 99.9% bacterial killing. For the single-dose profile of avibactam, growth recommenced after the 12-h time point when the concentration of avibactam on the exponentially declining concentration-time curve was 0.15 mg/liter, resulting in an estimated critical concentration threshold (CT) of ≤0.15 mg/liter. Adapted and republished from reference 43.